Antoice,
The Haswell processor's power management capabilities were a vast improvement over that of previous generations. In fact, when the processor goes into its lowest power states, its power draw can be so low that many power supplies intended for previous generation systems see this as an error and shutdown. You need to ensure that the power supply you are using is certified for Haswell. There are multiple sources for such certification lists. The alternative is to disable the use of these lower power states (C6/C7). This can be done form the Power Settings scene in Visual BIOS. This causes your system to draw more power all the time, however...
...Scott